i know this ding dong who had a few xbows blow up on him....he was using the same bolts from xbow to xbow......turned out his bolts were to light, and the xbow was basically dry firing( from what the xbow knew)...had his dogs never ate his bolts, he woulda never knows....lucky for him his fnl had some heavy ones to loan him..they worked great...one day he went and bought new ones, basically what he had before, and BOOM..IT WENT AGAIN...it has been a few years now and no explosions for him. is that what it was? we aint fer sure...but it sure seems apparent.